If you haven't dived into the pages of The Silmarillion, there's a whole cosmology of J.R.R. Tolkien's Middle-earth that you may not know. This short video outlines the basics, explaining as much about the universe's divine and angelic beings as you can learn in four minutes.

YouTuber CGP Grey made this primer on The Lord of the Rings' mythology, with a little artistic help from deviantART user kittyninjafish, who provided the illustrations. It's not a substitute for reading The Silmarillion, but it gives you a very basic idea about who is who in Tolkien's mythos.